Compact casing head and hanger



1967 E. K. PIERCE, JR 3,354,962

. COMPACT CASING HEAD AND HANGER I Filed Jan. 5, 1964 9 av 3 7 f6 4/ 56 r Z0 -44 6 k 34 66' I "if" a 52 70 &

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fro/swans" United States Patent Office- 3,3543% Patented Nov. 28, 1967 3,354,962 COMPACT CASING HEAD AND HANGER Elwood K. Pierce, Jr., Houston, Tex., assignor to Gray Tool Company, Houston, Tex., a corporation of Texas Filed Jan. 3, 1964, Ser. No. 335,563 6 Claims. (Cl. 166-89) This invention relates to tubing and/or casing and in are relatively compact in size.

In drilling oil and gas wells it is customary to case or line the hole with several different sizes of casing, starting at the top with a relatively large casing and employing smaller sizes in a telescopic manner until reaching the proper depth, each size being cemented off at its lower end and suspended from its upper end by a hanger and easing head arrangement. Usually a separate hanger and easing head is provided for each string of casing and for the tubing, the first hanger and head being mounted on the outer or surface casing, the second hanger and head being mounted on the first head by means of releasable clamps or bolted flanges and other hangers and heads being mounted in sequence in a similar manner.

Under some circumstances unitary head arrangements are provided which are adapted to suspend two or more strings of casing together with tubing within a single, unitary head structure. The internal arrangement and construction of these head structures is such as to provide a single head which may be used in place of the plurality of heads normally employed in completing a well head assembly. In one type of arrangement the hanger structures for the later positioned casing strings are more or less nested within the hanger structures for the earlier positioned strings so that a compact assembly of reduced height is achieved. In another type of unitary head arrangement the head is provided internally with a single deep bowl presenting a single tapered surface upon which the several hangers seat one above another.

The initial installation of a unitary head on the surface casing or the like effects substantial savings in subsequent rig time because blowout preventers mounted on the compact head may be left in place until the Christmas tree is to be installed. In addition, the unitary head eliminates time spent in installing additional hangers and heads and reduces the number of connections which must be made and consequently reduces the hazard of leaks. These savings in time and in the number of manipulations steps are of great importance in conducting remote operations such as encountered in underwater work.

Unitary head assemblies of the nesting type are, however, susceptible of improvement because in prior assemblies it has been conventional to provide a single hanger and a single hanger seat which support all of the strings of casing and in some instances the tubing also. That is, the hanger for the first-suspended string rests on the single seat and the later-suspended strings are seated on top of or inside the first hanger so that high stresses and consequent bearing failure may occur at the single hanger seat. This problem can be alleviated by increasing the size of the seat, but this solution detracts from the compactness of the head.

In the deep-bowl type of unitary head each hanger is supported directly from the single large deep bowl. This arrangement, of course, requires a continually increasing head diameter as well as considerable head height and therefore is not actually a compact arrangement.

It is the primary object of the present invention to provide a hanger and head arrangement which has both compact size and a reduced liability to bearing failure along the seating surfaces between the head and the suspended structures.

well heads for suspending particular to heads which It is a further object to provide a hanger and head arrangement in which a first-installed hanger receives the load from later-installed hangers and transmits the greater part of it laterally to the head at a location above the seat for the first-installed hanger.

It is a still further object to provide a hanger for an arrangement of the above type in which the hanger is provided above its primary seating surface, with an upwardly projecting expandable extension having an outer downwardly facing tapered shoulder for engagement with a complementary seat in a head and an inner, upwardly facing tapered shoulder for receiving a second hanger.

The invention will be further understood from the following detailed description taken with the drawing in which:

FIGURE 1 is an elevational view, partly in section, of a well head assembly embodying the principles of the present invention; and

FIGURE 2 is a fragmentary elevational view, partly in section, of a modification of the well head assemby of FIGURE 1.

Referring to FIGURE 1 there is shown a well head assembly 10 which includes, as primary components, a unitary compact casing and tubing head 12 mounted on top of a casing 14, for example 13% inch casing, and containing in ascending order a first casing hanger 16, a second casing hanger 18 and a tubing hanger 20. The lower casing hanger 16 is provided with a downwardly projecting, interiorly threaded extension 22 spaced inwardly from the wall of the casing and tubing head 12 by which a first string of casing 24, for example 9 /8 inch casing, is suspended. The upper casing hanger 18 has a lower interiorly threaded extension 26 spaced inwardly from the lower hanger 16 from which a second string of casing 28, for example 7 inch casing, is suspended. The tubing hanger 20 suspends a single tubing string 30, for example 3 /2 inch tubing, and is itself supported on top of the upper casing hanger 18.

The tubing hanger 20 is of the stufling box type in which an annular seal 32 grips the exterior of the tubing string 30. A bottom extension 34 on the tubing hanger 2G is spaced inwardly from the head 12 and is provided with a plurality of lateral circulation ports 36 communieating with the annulus between the tubing 30 and the extension 34 and with the annulus between the extension 34 and the head 12. The upper portion of the tubing hanger 20 is provided with annular sealing rings 38 and an annular groove for receiving hold-down screws 40 which extend through the head 12. Above the top of the head 12 the tubing 30 connects with a threaded plug bushing 42 which is retained in a flanged cap member 44 bolted to the top of the head 12. In practice suitable valving and a production line will be connected to the top of the cap member 44 for receiving the flow from the tubing 30.

According to the principles of the invention the unitary compact head 12 and the upper and lower hangers 18 and 16 are designed to have the smallest possible pressure area yet avoid danger of bearing failure along the supporting surfaces. To achieve these advantage the upper casing hanger 18 is arranged to nest partly within and be supported by the lower casing hanger 16 and the latter is provided with two vertically spaced seats which transmit the load to the head 12 in a predetermined manner.

The lower hanger 16 is supported by the head 12 primarily along an exterior, downwardly facing tapered shoulder 46 which is located on a cylindrical center portion of the hanger 16 below a pair of spaced sealing rings 48 and which rests on a complementary seat within the head 12. Integral with the center portion of the lower hanger 16 is an upwardly projecting annular extension 50 having an exterior sealing surface 52 which is tapered slightly inwardly and downwardly for engagement with a complementary seat within the head 12. This seat has, of course, a minimum diameter of sufficient size to permit the body portion of the hanger 16 to pass by during the landing of the casing string 24. The inner surface of the extension 50 is tapered inwardly and downwardly at 54 to a greater extent than the surface 52 so as to form a seat for the upper hanger 18. A plurality of circulation ports 55, extend through the extension 50 below the tapered surfaces.

The upper hanger 18 includes, in addition to its lower extension 26, an upper cylindrical portion 56 which engages the bore of the head 12 above the lower hanger 16. Intermediate the extension 26 and the upper portion 56 the upper hanger 18 is provided with an exterior tapered surface which engages the seat 54 in the lower hanger 16. Suitable sealing rings 58, 60 and 62 are provided between the upper hanger portion 56 and the bore of the head 12 and at the seats 54 and 52, respectively.

The unitary compact head is provided with the usual outlets, hanger hold-down screws and test ports. As shown, flanged lateral outlet 64 communicates with the annulus between the tubing string 30 and the casing string 28, another flanged outlet 66 communicates with the annulus between the casing strings 28 and 24 and an interiorl-y threaded port 68 communicates with the annulus between the casing string 24 and the supporting casing 14. The upper and lower casing hangers 18 and 16 are locked in place by hold-down screws 70 and 72, respectively, which engage annular exterior grooves in the upper portions of the hangers. Two test ports 74 are provided in the wall of the head 12 between the sealing rings 58 associated with the upper hanger 18 and two more test ports 76 are provided between the sealing rings 48 associated with the lower hanger 16.

FIGURE 2, in which primed reference numerals identify elements already described, illustrates a well head assembly in which the principles of the invention are applied to slip-type hangers. As shown a lower casing hanger 16 is carried in a unitary compact head 12' primarily on a lower seat 46 and secondarily on an upper seat 52'. A string of casing 24' is suspended by the lower hanger by means of slips 78. A sealing ring 80 below the slips 78 is expanded into tight engagement with the casing 24' and the hanger 16' by the weight of the casing 24. An upper casing hanger 18' is carried by the lower casing hanger 16 in generally nesting relationship at a tapered seat 54' formed on the inner bore of an extension on the lower hanger 16. An inner casing string 28 is suspended from the upper hanger 18 by conventional slips 82 and seals 84. A string of tubing 30' is suspended from a tubmg hanger having a lower extension 34, which rests on top of the upper casing hanger 18.

The well head assemblies 10 and 10' are assembled by generally conventional procedures which will not be described in detail except to the extent that they affect or are affected by the novel design of the casing hangers and the interior configuration of the unitary compact head 12. Since the assemblies 10 and 18 differ only in the use of slips in place of a threaded connection between the casing hangers and their casing strings, a description of the procedures associated with one of the assemblies will suffice. Referring to FIGURE 1 the lower casing hanger 16 and its casing string 24 is landed in the head 12 in the usual manner after the well has been drilled and the supporting casing 14 and head have been installed. This may be accomplished, for example, by threading the lower end of a drill pipe into the inner bore of the hanger 16 and lowering it along with its casing string 24 through the head 12 by means of a draw works. The hanger 16 is so designed and constructed that as it descends its upper extension 50 seals against the tapered surface 52 and then the lower shoulder lands on the seat 46, the extension 50 actually deflecting inwardly to a slight degree as landing occurs. The hanger 16 is thus supported at 52 and 46.

After the well hole has been drilled further, the upper casing head 18 with its casing string 28 attached is lowered through the head 12 to engage its exterior tapered surface with the interior seat 54 on the lower casing head 16. The load of the upper hanger 18 is thereby transmitted to the head 12 principally in a lateral direction through the seat 52, only a small portion being transmitted to the seat 46. It will be appreciated that the extent to which this load is transmitted laterally rather than downwardly depends on the relationship among the tapers of the seats, 46, 52 and 54. To effect lateral transmission of the load, the taper of the seats 52 and 54 on the extension of the lower hanger are, of course, less than the taper of the lower seat 46. As shown, the taper of the seat 54 is greater than the taper of the seat 52, but the precise relationship of these tapers is not critical. It will be appreciated also that the extension on the lower hanger 16 should preferably be constructed so as to be laterally defiectable by the forces exerted on the seats. This will assure that the weight of the upper hanger 18 and its casing string 28 will be transmitted to the head 12, primarily in a lateral direction at the seat 52, rather than in a downward direction at the seat 46.

When the well hole has been drilled further the tubing 38 is run in and suspended by means of the tubing hanger 20 on the top of the upper casing head 18. The upper surface of the casing hanger 18 and the lower surface of the lower extension 34 on the tubing hanger 20 are machined flat to assure even distribution of the load. The load is transmitted downwardly through the hanger 18 to the seat 54 and then primarily laterally to the head 12 through the seat 52. Completion of the well head assembly is then effected in a conventional manner employing the usual procedures.

A further advantage associated with the head and hanger arrangement of the invention is that one size control equipment may be utilized during construction of the well once the supporting casing 14 has been cemented in place and the head 12 attached thereto.

From the above description it will be appreciated that the hanger and head assembly of the invention provides a unitary assembly which maintains a very small pressure area for suspending the hangers and which suspends the successive casing strings within a short vertical space. The assembly is therefore not only compact, but by virtue of the double tapered extension 50 on the lower hanger it avoids the possibility of bearing failure by transmitting some of the load laterally to the head above the lowermost hanger seat. While a specific embodiment of the invention has been described and illustrated, it is not intended that the details thereof be limiting except as they appear in the appended claims.

What is claimed is:

1. In a well head assembly: a compact unitary head for receiving hangers and associated strings of pipe, said head including a unitary body member having a vertical bore therethrough, said bore defining an upper annular tapered seat and a lower annular tapered seat concentric with and disposed below said upper seat, said upper seat facing more toward the vertical than said lower seat; a hanger member in engagement with and supported on said upper and lower seats, said hanger member including a unitary tubular body having a lower portion, an upwardly extending annular extension and means associated with said lower portion for suspending a string of casing therefrom, said extension having a downwardly facing annular shoulder in mating engagement with said upper seat and said lower portion having a downwardly facing annular shoulder in mating engagement with said lower seat, the relative vertical distances between said shoulders and between said seats being such that the shoulder on said extension engages said upper seat before the shoulder on said lower portion engages said lower seat when said hanger member is lowered into said head, said extension being of radially defiectable construction relative to said lower portion and, in the final position of said hanger member, being deflected radially inwardly from its undeflected position by engagement with said upper seat whereby the weight of a casing string suspended by said suspending means will be supported partially by said upper seat and partially by said lower seat.

2. Apparatus as in claim 1 including a second hanger member supported by said extension and means associated with said second hanger member for suspending a string of pipe therefrom, said second hanger member having a downwardly facing annular shoulder engaging an upwardly facing annular seat on said extension whereby the more nearly vertical taper at said upper seat in the bore of said head together with the radial deflectability of said extension will transmit downward forces generated by the weight of said second hanger member in a primarily lateral direction to said head through said upper seat.

3. Apparatus as in claim 1 wherein the bore of said extension has an upwardly facing annular tapered seat which faces more toward the vertical than said lower seat in said head, said apparatus further including a second hanger member supported on said seat in the bore of said extension and means associated with said second hanger member for suspending a string of easing therefrom whereby the more nearly vertical taper of said last-named seat and of said upper seat in said head together with the radial deflectability of said extension will transmit forces generated by the weight of said second hanger member in a primarily lateral direction to said head through said upper seat.

4. Apparatus as in claim 3 including a third hanger member and associated suspending means supported by said second hanger member.

5. Apparatus as in claim 3 wherein said hanger member which engages said seats in a bore of said head is provided with a radial port at a location between its upper and lower shoulders, and wherein said head is provided with a lateral outlet which communicates with said port.

6. Apparatus as in claim 1 wherein said deflectable extension on said hanger means is defined by a hollow, generally cylindrical wall extending upwardly from said lower portion of said hanger member, the thickness of said wall being less than the thickness of the wall which defines said lower portion.

References Cited UNITED STATES PATENTS 1,625,378 4/ 1927 Snodgrass 285-144 X 2,1 l8,094 5/1938 McDonough et al. 285- X 2,889,886 6/11959 Gould 166-89 3,105,552 10/1963 Haeber et al. 285-140 X 3,168,337 2/1965 Johnson et al. 285-140 X 3,190,354 6/1965 Stone 166-89 FOREIGN PATENTS 1,250,353 11/1960 France.

EDWARD c. ALLEN, Primary Examiner. THOMAS P. CALLAGHAN, Examiner. 

1. IN A WELL HEAD ASSEMBLY: A COMPACT UNITARY HEAD FOR RECEIVING HANGERS AND ASSOCIATED STRINGS OF PIPE, SAID HEAD INCLUDINGA A UNITARY BODY MEMBER HAVING A VERTICAL BORE THROUGH, SAID BORE DEFINING AN UPPER ANNULAR TAPERED SEAT AND A LOWER ANNULAR TAPERED SEAT CONCENTRIC WITH SAID DISPOSED BELOW SAID UPPER SEAT, SAID UPPER SEAT FACING MORE TOWARD THE VERTICAL THAN SAID LOWER SEAT; A HANGER MEMBER IN ENGAGEMENT WITH ANS SUPPORTED ON SAID UPPER AND LOWER SEATS, SAID HANGER MEMBER INCLUDING A UNITARY TUBULAR BODY HAVING A LOWER PORTION, AN UPWARDLY EXTENDING ANNULAR EXTENSION AND MEANS ASSOCIATED WITH SAID LOWER PORTION FOR SUSPENDING A STRING OF CASING THEREFROM, SAID EXTENSION HAVING A DOWNWARDLY FACING ANNULAR SHOULDER IN MATING ENGAGEMENT WITH SAID UPPER SEAT AND SAID LOWER PORTION HAVING A DOWNWARDLY FACING ANNULAR SHOULDER IN MATING ENGAGEMENT WITH SAID LOWER SEAT, THE RELATIVE VERTICAL DISTANCES BETWEEN SAID SHOULDERS AND BETWEEN SAID SEATS BEING SUCH THAT THE SHOULDER ON SAID EXTENSION ENGAGES SAID UPPER SEAT BEFORE THE SHOULDER ON SAID LOWER PORTION ENGAGES SAID LOWER SEAT WHEN SAID HANGER MEMBER IS LOWERED INTO SAID HEAD, SAID EXTENSION BEING OF RADIALLY DEFLECTABLE CONSTRUCTION RELATIVE TO SAID LOWER PORTION AND, IN THE FINAL POSITION OF SAID HANGER MEMBER, BEING DEFLECTED RADIALLY INWARDLY FROM ITS UNDEFLECTED POSITION BY ENGAGEMENT WITH SAID UPPER SEAT WHEREBY THE WEIGHT OF A CASING STRING SUSPENDED BY SAID SUSPENDING MEANS WILL BE SUPPORTED PARTIALLY BY SAID UPPER SEAT AND PARTIALLY BY SAID LOWER SEAT. 